Do you have an overweight male rat for a father? If so, you could be at increased risk of adult-onset diabetes, according to researchers at the University of New South Wales, published in Nature. The female offspring of male rats fed a high-fat diet were shown to develop early-onset glucose intolerance and impaired insulin secretion, even if they themselves were not overweight, suggesting that a high-fat diet alters sperm development. Yesterday it was revealed that one in 20 British adults is now being treated for diabetes, costing the NHS £9bn each year.